This was one of the first novelisations I ever bought (though I already had The Abominable Snowman - IIRC I bought this one because I recognised the yeti on the cover) and it completely terrified me. I seem to recall setting it aside because I couldn't continue it, and eventually got through it by reading backwards from the end in chunks.

We had a local "Children's Bookshop" with a whole shelf devoted to targets. I used to spend a lot of time in there (though not so much money since pocket money only goes so far) pondering precisely which book to purchase next. This was definitely one of the earlier purchases.